1. Field of the Invention
This invention is directed in general to security systems and in particular, to a wireless security system in which a signaling device, which operates with a transmitter, is capable of receiving and verifying coded signals from the transmitter. The transmitter transmits the coded signals using a different data frame pattern during each transmission.
2. Prior Art
Transmitter-receiver controller systems are widely used for remote control and/or actuation of devices or appliances such as garage door openers, gate openers, and security systems. For example, most conventional security systems use a transmitter-receiver combination to monitor selected areas. In such conventional security systems, all the peripheral devices such as sensors, and the control unit operate using the same identification code, so that only those devices belonging to a particular installed security system on the premises can operate with each other. Other devices which operate using a different identification code, would be ignored. In more complicated systems, various groups of peripheral devices may be assigned to different zones, each of which is monitored for quick identification in the event of a security breach.
Such conventional security systems create security risks. Since a single, fixed identification code is utilized, the identification code may be detected by a hostile user, and subsequently used to disarm the control unit. Further, a single, fixed identification code may be generated by a non-system source and incorrectly recognized as a system signal.
Accordingly, there is a need in the technology for a security system which provides increased security by having a control unit which operates with a number of peripheral devices, each having different identification codes which cannot be easily detected. In addition, there is a need for a security system which improves receiver immunity to spurious signals by using a different data frame pattern during each transmission.
A signaling device that receives coded signals from a transmitter is claimed. The signaling device comprises a first circuit that receives a first code from the transmitter. The first code includes a first identification code and a first variable code. The signaling device further comprises a memory that stores a second code. The second code includes a second identification code and a second variable code. The signaling device further comprises a second circuit coupled to the first circuit and the memory. The second circuit generates an output signal if the first code matches the second code. The signaling device further comprises an annunciator circuit coupled to the second circuit. The annunciator circuit provides a perceivable indicator if the second circuit generates the output signal.